Strainer

ABSTRACT

A conduit has a first end and interior and exterior surfaces extending downstream from the first end. A strainer has a first end and a second end. An upstream portion of the strainer is positioned engaging a projection on the interior surface of the conduit to resist downstream shifting of the strainer. A strainer body extends at least partially downstream of the upstream portion. The apparatus may be used as a strainer/coupler and may be used to filter water in a chiller apparatus.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of Ser. No. 10/350,634, filed Jan. 24, 2003, thedisclosure of which is incorporated by reference herein as if set forthat length.

BACKGROUND OF THE INVENTION

This invention relates to fluid handling, and more particularly to thestraining of aqueous heat transfer fluids in refrigeration systems.

Industrial refrigeration is a well developed field. Many systems involvetransferring heat to or from an aqueous solution, often essentiallywater. The heat may be exchanged with a refrigerant passing along in aclosed-loop refrigeration cycle. In many systems, the cooled fluid iswater which may flow in a closed loop (e.g., for building or industrialcooling) or in an open loop (e.g., for consumption). In water-cooledchillers, the heated fluid is also water. It is advantageous to strainthe fluid to prevent clogging of or damage to system components.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention is an apparatus having a conduit and astrainer. The conduit has a first end, interior and exterior surfacesextending downstream from the first end, and a projection on theinterior surface. The strainer has a first end and a second end. Anupstream portion of the strainer is positioned to engage the conduitprojection to resist downstream shifting of the strainer. A strainerbody extends at least partially downstream of the upstream portion.

The apparatus may be used as a coupler for connecting first and secondfluid conducting members and extending along an axis between the firstend and a second end. The exterior surface proximate the conduit firstand second ends may be adapted for connection to the first and secondfluid conducting members. Such adaptation may comprise first and secondrecesses at first and second locations relatively close to the first endand to the second end, respectively. The apparatus may further includefirst and second clamps for respectively securing the conduit to thefirst and second fluid conducting members. The first recess may beaxially aligned with the projection such as being commonly formed by anannular indentation from the exterior.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a chiller system.

FIG. 2 is a partial longitudinal sectional view of a strainer/couplerassembly of the system of FIG. 1.

FIG. 3 is an end view of the strainer/coupler assembly of FIG. 2.

FIG. 4 is a detailed longitudinal sectional view of an upstream endportion the strainer/coupler assembly of FIG. 2.

FIG. 5 is a partial longitudinal sectional view of an alternatestrainer/coupler assembly.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 shows a chiller system 20. The system includes two heatexchangers: an evaporator (cooler) 21; and a condenser 22. A first flowfrom a condenser pump 24 passes through the condenser 22 and a secondflow from a cooler pump passes through the cooler 21.

The exemplary system is a water-cooled system in which a refrigerationsubsystem 30 has a refrigerant flow path that transfers heat to thefirst flow in the condenser and draws heat from the second flow in theevaporator. The condenser and cooler pump 24 and 26 respectively haveoutlet conduit assemblies 50 and 52 connecting such pumps to the heatexchanger and inlet conduit assemblies 54 and 56 receiving water from anoutside condensing water loop and a chilled water loop (building orindustrial process return).

In a exemplary use, the evaporator produces chilled water that may beused, for example, for air conditioning a building or cooling anindustrial process. The condenser 22 is coupled to an appropriateexternal heat rejection system (not shown). Exemplary heat rejectionsystems may be an open loop cooling tower or a closed loop air-cooledliquid cooler.

To protect the pumps from damage and the heat exchanger from clogging,strainers are advantageously provided in both the condenser and coolerflow path loops. In the exemplary embodiment, both inlet conduitassemblies 54 and 56 have an inventive strainer/coupler assembly 60joining upstream and downstream conduit sections 62 and 64. Eachassembly 60 includes a sleeve 66 and upstream and downstream clamps 68and coupling the sleeve to the upstream and downstream conduits and 64.In the exemplary embodiment, the conduits 62 and and sleeve 66 areformed of steel pipestock with rolled clamp grooves (described below)near their ends.

FIG. 2 shows further details of the strainer/coupler 60. The sleeve 66extends from an upstream end 80 to a downstream end 82 and has a centrallongitudinal axis 500. An exemplary sleeve length is 10 cm. The sleevehas inner (interior) and outer (exterior) surfaces 84 and 86. Theupstream and downstream rolled clamp grooves 88 and 90 each define anannular recess 92 in the exterior surface and a rib or annularprojection 94 in the interior surface.

Each exemplary clamp 68 and 70 has a split body, the two halves 100 and102 (FIG. 3) of which are secured to each other via a pair ofdiametrically opposite threaded bolt/nut assemblies 104. An exemplaryclamp body is formed of steel and has a pair of radiallyinwardly-projecting upstream and downstream lips 110 and 112 (FIG. 2).The upstream lip of the downstream clamp 70 is compressively engaged tothe sleeve in the recess 92 of the downstream groove 90. The downstreamlip of the downstream clamp 70 is similarly compressively engaged to anupstream recess in the downstream conduit 64 of FIG. 1. Similarly, thedownstream lip of the upstream clamp 68 is compressively engaged to thesleeve in the recess of the upstream groove and the upstream lip of theupstream clamp is compressively engaged to a similar recess in theupstream conduit 62 of FIG. 1. Each clamp body carries an elastomericgasket 120 (FIG. 2) for providing a seal between the sleeve and adjacentthe conduit.

The strainer/coupler assembly 60 further includes a strainer 140. Theexemplary strainer 140 comprises a foraminate element 142 having anupstream interior and a downstream exterior. The exemplary foraminatemember is formed as a wire mesh (e.g., of 0.5 mm stainless steel wire ina 15 mesh). The exemplary mesh is rolled into a generally frustoconicalconfiguration and welded along a seam 144 (FIG. 3) to extend from a rimat an upstream end 146 of the element to a downstream end 148. Otherforming techniques and other foraminate materials (e.g., perforatedmembers, molded foraminate members, etc.) may be used. An upstream endportion of the foraminate member 142 is secured to a ring 150 capturedwithin the sleeve upstream of the groove 88. In the exemplaryembodiment, the ring 150 is formed of sheet metal (e.g., a stainlesssteel strip 14 mm wide and 1 mm thick) having an interior surface 152and an exterior surface 154 and upstream and downstream ends or rims 156and 158, respectively. The downstream rim 158 abuts an upstream-facingend of the rib 94 to prevent downstream movement of the ring and thusthe strainer element. In the exemplary embodiment, the foraminate member142 is secured to the ring such as by welding an exterior portion of theforaminate member adjacent the upstream end 146 to the interior surface152 of the ring.

For installation of the strainer, the strainer may be inserted into thesleeve through the upstream end thereof until the ring 150 seatsupstream of the groove 88. In this installed condition, the ringupstream end 156 and foraminate element downstream end 148 definerespective upstream and downstream ends of the strainer 140. The lengthof the foraminate element downstream of the portion secured to the ringis advantageously chosen to provide sufficient straining surface area.In the exemplary embodiment, the downstream end 148 of the foraminateelement is located longitudinally between the downstream groove 90 andsleeve downstream end 82. Advantageously, the downstream end 148 islocated downstream of the upstream groove 88 and, more advantageously,downstream of a midpoint of the sleeve so as to provide a desired amountof surface area. Advantageously, the downstream end 148 remains upstreamof the sleeve downstream end 82 so that the recessing of the strainermay protect the strainer from damage during assembly or disassembly ofthe inlet conduit assemblies.

For installation of the strainer/coupler, the sleeve is then placedbetween the adjacent conduits and the clamps are put in place and theirbolts/nuts tightened to secure and seal the sleeve ends to therespective conduits. Disassembly for perodic cleaning of the strainer ata cleaning interval or replacement at a replacement interval or as mayotherwise be required is by a reverse of this process.

FIG. 5 shows an alternate strainer/coupler assembly 200 having a sleeve202 and a strainer 204 which, except as described below, may be similarto the sleeve 66 and strainer 140 of the strainer/coupler assembly 60.In the strainer 204, the downstream end 205 of the foraminate element206 is open. In the exemplary embodiment, this open end is surrounded bya conduit 208 (e.g., a stainless steel tube with an upstream end 210soldered to the exterior of the foraminate element and a downstream end212 within a transverse conduit (e.g., a pipe) 220 extending through thesidewall of the sleeve 202. One end 222 of the pipe 220 within thesleeve is closed. The other end 224 is coupled to a valve 226 (e.g., alever-actuated ball valve threaded into the pipe end). In normaloperation, the valve 226 is closed blocking communication through thepipe 220 and, thereby, the downstream end of the strainer 204. Thestrainer operates as heretofore described. Periodically, however, thestrainer may be flushed of solid contaminants by opening the valve 226and, thereby permitting a flow from the interior of the strainer throughthe downstream end 205 and tube 212 into the pipe 220 and out an outlet228 of the valve. This flushing flow may be maintained for anappropriate interval. Despite such flushing, periodically the strainermay still need to be replaced. Strainer replacement is eased by having anonpermanent engagement between the strainer and the pipe 220. In theexemplary embodiment, the tube 208 is closely fit within an aperture inthe pipe sidewall with a clearance similar to or smaller than the meshopening size of the strainer. This clearance advantageously permits easyremoval of an old strainer and insertion of a new strainer withoutcompromising filtration.

One or more embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, details of any particular application may influence attributesof the strainer/coupler assemblies. Accordingly, other embodiments arewithin the scope of the following claims.

1. A system comprising: a heat exchanger having first and second flowsin thermal communication; and a first pump driving said first flow andhaving an inlet conduit for receiving the first flow and an outletconduit coupled to the heat exchanger for delivering the first flow,wherein the inlet conduit comprises an assembly of: an upstream conduit;a downstream conduit, optionally integral with the first pump; anintermediate conduit; means for straining the first flow; and means forcoupling the intermediate conduit to the upstream and downstreamconduits.
 2. The system of claim 1 further comprising: a second pumpdriving said second flow an having an inlet conduit for receiving thesecond flow and an outlet conduit coupled to the heat exchanger fordelivering the second flow, wherein the second pump inlet conduitcomprises an assembly of: an upstream conduit; a downstream conduit,optionally integral with the second pump; an intermediate conduit; meansfor straining the second flow; and means for coupling the second pumpintermediate conduit to the second pump upstream and downstreamconduits.
 3. A system comprising: a heat exchanger having first andsecond flows in thermal communication; and a first pump driving saidfirst flow and having an inlet conduit for receiving the first flow andan outlet conduit coupled to the heat exchanger for delivering the firstflow, wherein the inlet conduit comprises an assembly of: an upstreamconduit; a downstream conduit, optionally integral with the first pump;an intermediate conduit; a strainer at least partially within theintermediate conduit; and first and second clamps respectively couplingthe intermediate conduit to the upstream and downstream conduits.
 4. Asystem comprising: a heat exchanger having first and second flows inthermal communication, the first flow consisting essentially of water;and a conduit assembly carrying the first flow and comprising: a firstconduit; a second conduit downstream of the first conduit; a clampsecuring the first conduit to the second conduit and having a firstportion engaged to a clamping recess on the second conduit; a strainerat least partially within the second conduit and retained againstdownstream movement by engagement with an interior projection of thesecond conduit inboard of the recess.
 5. The system of claim 4 wherein:the strainer is entirely within the second conduit; the first conduit isan upstream conduit; there is a downstream conduit; the second conduitis an intermediate; and a second clamps couples the intermediate conduitto the downstream conduit.
 6. The system of claim 4 wherein: a thirdconduit extending through a sidewall of the second conduit and has afirst portion in fluid communication with a downstream portion of thestrainer and a second portion coupled to a valve for selectivelyestablishing communication between the strainer and a destinationexternal to the second conduit.
 7. The system of claim 4 wherein thestrainer has: a sheet metal sleeve; and a strainer body comprising afrustoconical sidewall secured to said sheet metal sleeve and extendingdownstream of to a radially-extending end portion.
 8. The apparatus ofclaim 7 wherein: the strainer body consists essentially of a wire mesh.